Co/Rhheterobimetallic nanoparticles were prepared from cobalt-rhodium carbonyl clusters [Co2Rh2(CO)12 and Co3Rh(CO)12] and immobilized on charcoal. HR-TEM revealed that the size of the heterobimetallic nanoparticles was ca. 2 nm and ICP-AES analysis showed a 2 : 2 and a 3 : 1 cobalt-rhodium stoichiometry (Co2Rh2 and Co3Rh1) in the heterobimetallic nanoparticles. The Co/Rhheterobimetallic nanoparticles
Copper(I)-Catalyzed Kinetic Resolution of <i>exo</i>-3-Oxodicyclopentadienes and <i>endo</i>-3-Oxodicyclopentadiene
作者:Xin Chang、Xi-Shang Sun、Chao Che、Yuan-Zheng Hu、Hai-Yan Tao、Chun-Jiang Wang
DOI:10.1021/acs.orglett.9b00136
日期:2019.2.15
The first example of highly efficient kineticresolution of exo-3-oxodicyclopentadienes and endo-3-oxodicyclopentadiene has been developed by means of Cu(I)-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylide. Compared with the existing methodologies for those synthetically important optically active convex molecules, the current protocol provides an alternative but more practical approach
Catalytic Pauson–Khand Reaction in Ethylene Glycol–Toluene: Activity, Selectivity, and Catalyst Recycling
作者:Xavier Verdaguer、Antoni Riera、Albert Cabré
DOI:10.1055/s-0037-1610441
日期:2018.10
additive in the catalytic Pauson–Khand reaction (PKR) is reported. In most cases both the yield and selectivity were enhanced compared to standard protocols. Moreover, the immiscibility of ethylene glycol in toluene allowed recycling of the catalyst (which remained mainly in the ethylene glycol). The recycling allowed catalyst loading to be reduced to only 3 mol%. A gram-scale reaction was also performed
Preparation of an amine N-oxide on solid phase: an efficient promoter of the Pauson–Khand reaction
作者:William J. Kerr、David M. Lindsay、William J. Kerr、David M. Lindsay
DOI:10.1039/a908267k
日期:——
A novel, recyclable polymer-supported amine N-oxide has been prepared and shown to be a good promoter of the PausonâKhand reaction under mild conditions, affording good to excellent yields of cyclopentenones.
Intermolecular additive free microwave (MW) promoted and cobalt octacarbonyl mediated Pauson-Khand reaction (PKR) performance was improved for estrone ring extension. The reaction development with norbornene and cyclopentene produced cyclopentenones in yields of comparable levels with those previously obtained with the aid of chemical additives as promoters. The PKRs with norbornene demonstrated that a low cobalt complex concentration increases yields, especially for the aliphatic alkynes. Furthermore, a boost for the MW PKR could be obtained by a gradual cobalt complex addition. These expedients combined with the use of an excess of free and cobalt complexed alkyne led to successful estrone ring system extension with various alkynes. (C) 2008 Elsevier Ltd. All rights reserved.